If a patient has an unstable pelvic fracture, do you transfer or apply an external fixator first?

The 2009 Orthopaedic Trauma Association (OTA) Specialty Day addressed a variety of fracture management controversies, including current surgical indications and techniques for problem pelvic and acetabular fractures. Michael T. Archdeacon, MD, MSE, and Alexandra K. Schwartz, MD, faced off on the question of whether to transfer a patient with an unstable pelvic fracture or to apply an external fixator.

Transfer the patient for definitive care
According to Dr. Archdeacon, “Pelvic fractures are one of the true (few) life-threatening orthopaedic emergencies,” and patients should be transferred for definitive care as quickly as possible. The overall mortality rate for patients with pelvic fractures is between 10 percent and 20 per-cent. That rate jumps to 38 percent if the patient is hypotensive on admission, and to 50 percent if the patient has an open pelvic fracture.

Treating such injuries requires aggressive management, an experienced team, and a multidisciplinary approach characteristic of an advanced trauma center. Patients with pelvic fractures also frequently have associated injuries. As many as two thirds of patients with pelvic fractures may also be in shock; as many as 60 percent have neurologic damage. Other associated injuries include acute respiratory distress, thoracic injuries, intra-abdominal injuries, and urologic injuries.

“In treating patients with pelvic fractures, the first step is to identify those patients at high risk for mortality,” said Dr. Archdeacon. He noted that patients with blunt trauma injuries or mechanically unstable pelvic fractures and those who are elderly or hemodynamically unstable are at high risk.

But, he cautioned, high risk patients aren’t always easily identifiable. A radiograph showing bilateral acetabular fractures, bilateral rami fractures, and symphysis diastasis is obviously indicative of a patient at high risk of mortality (Fig. 1). But a radiograph of an elderly patient with little physiologic reserve who fell on the ice and sustained an isolated acetabular fracture may be overlooked, even though the patient nearly exanguinated (Fig. 2)

“Managing the unstable pelvic fracture is a four-step process: identification, resuscitation, immobilization, and transportation (to the trauma center),” said Dr. Archdeacon. Radiographic evaluation, a pelvic examination, and hypotension can be used to identify an unstable pelvic fracture. A pelvic binder, a pelvic clamp, or a sheet wrap may be used to immobilize the injury.

A sheet wrap is inexpensive, easy to apply, and easy to work around. Its long, broad surface can both reduce and maintain the fracture. “The key to using a sheet wrap,” advised Dr. Archdeacon, “is to apply it around the center of the trochanter, not at the iliac crests (Fig. 3). It should not be used like a rope around the pelvis.”

Take time to apply an external fixator
“Transferring hemodynamically unstable patients who have an unstable pelvic fracture without stabilizing the fracture can be dangerous,” said Dr. Schwartz. “Pelvic stability is an early and critical goal to decrease bleeding, decrease pain, improve mobility, and allow for transfers.”

Underestimating the hemodynamic status of young patients can be fatal, particularly because the retroperitoneum can contain up to 4 liters of blood. “External fixation can prevent dislodgement of clots, especially during transfers, and fracture reduction re-opposes bleeding osseous surfaces, thereby promoting clot formation and decreasing ooze,” she said.

Indications for pelvic external fixation include the following:

• Acute management of the patient with severe pelvic disruption and hemodynamic instability to control hemorrhage
• Early management of polytrauma patients to facilitate pulmonary toilet, nursing care, and decrease pain
• Definitive treatment for certain fractures
• Adjunct treatment to enhance posterior internal fixation

Dr. Schwartz pointed out that the timing of external fixator placement, the location of pin placement on the patient’s pelvis, and the contraindications for using an external fixator remain controversial. “If a patient is bleeding, should the external fixator be placed prior to or after angiography?”

Although waiting to apply external fixation until after angiography has shown good results in some series, immediate access to angiography and a skilled interventional radiographer is required, making this an institution-dependent decision. External fixation can be done quickly and safely, even in the angiography suite, and only 10 percent of patients with pelvic fractures have bleeding from a named artery. Applying external fixation prior to angiography also allows for compression of fracture sites and stabilizes the pelvis so clots may form.

“Applying an external fixator prior to an exploratory laparotomy prevents further destabilization of open book pelvic fractures by preventing the increase in symphyseal diastasis that can occur when the closed abdomen is opened,” she said.

Some patients should not get external fixation, admitted

Dr. Schwartz, including those with certain lateral compression fracture patterns, associated acetabular fractures, iliac wing fractures, severe soft-tissue injury at the pin insertion site, and Morel Lavalle lesions. A C-clamp must be considered for a pelvic ring injury with severe posterior ring injury.

“Hemodynamically unstable patients with unstable pelvic ring injury need aggressive, early treatment to minimize bleeding,” she concluded, “and external fixation can be an invaluable tool. It should be applied prior to transfer if the patient is unstable and angiography is not available, or if the patient is undergoing exploratory laparotomy.”

Dr. Archdeacon is a paid consultant for and receives research support from Stryker Trauma. Dr. Schwartz reports no conflicts.

Choosing a pelvic fixator
According to Dr. Schwartz, controversy exists not only on whether to use an external fixator, but also on what type to use. Anterior fixators include the anterior superior iliac spine (ASIS) pin and the anterior inferior iliac spine (AIIS); the C-clamp is a posterior frame.

Dr. Schwartz noted that the obturator outlet radiographic view allows for the best visualization for placement of the ASIS pin between inner and outer tables of the ilium. Additionally, ASIS pins are easier to insert than AIIS pins; the ASIS is more subcutaneous and should be used instead of the AIIS frame for patients in dire straits or when placing an external fixator without fluoroscopic imaging.

Although the AIIS frame is biomechanically stronger and does not interfere with acetabular fracture surgical incisions, it is more difficult to insert and may interfere with the patient’s ability to sit upright.

The pelvic C-clamp consists of two pins applied to the posterior ilium in the region of the sacroiliac joints, or a newer technique can be used and the pins are placed at the level of the greater trochanters. It provides compression and stability at the posterior ring, but may not be ideal for ilium fractures or transiliac fracture dislocations.

She cautioned, however, that frames of any construction or location, or use of multiple pins do not allow control of vertical instability.